Method for generating an on-screen menu

ABSTRACT

A method for generating an on-screen menu comprising menu buttons and other menu items, e.g. help text, is characterized in that one or more groups of menu buttons or menu items are defined, wherein a group comprises one or more menu buttons or menu items and has associated a defined area on the screen. A state is assigned to a button, the state being “enabled” or “disabled”, wherein only an enabled button or item may be displayed, and wherein within a group not more than one button or item may be enabled. The state of a button can be changed by commands associated with other buttons.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/448,659, filed Jul. 31, 2014, which is a continuation of U.S.application Ser. No. 14/248,809, filed Apr. 9, 2014, now U.S. Pat. No.8,887,094, which is a continuation of U.S. application Ser. No.13/900,666, filed May 23, 2013, now U.S. Pat. No. 8,745,530, which is acontinuation of U.S. application Ser. No. 10/586,294, filed May 18,2007, now U.S. Pat. No. 8,473,863, which is a 371 of InternationalApplication No. PCT/EP2004/014187, filed Dec. 13, 2004, which claimspriority to European Application No. EP04090035.9, filed Feb. 4, 2004,and European Application No. EP04090010.2, filed Jan. 14, 2004, hereinincorporated by reference.

FIELD OF THE INVENTION

This invention relates to a method for generating an on-screen menu.

BACKGROUND

Audio-visual contents of data storage media, e.g. Digital VersatileDiscs (DVD) for video applications, usually contain menu data forvarious applications, e.g. to enable a user to select specific contentof the medium. The menu data are used for rendering the menu on adisplay screen. Often so-called multi-page menus are used, where eachpossible state of the menu is represented by a full-screen image that isoverlaid as a separate layer to the video picture. The menu layer isusually transparent, except for the displayed menu items.

In state-of-the-art menus the menu items basically consist of a numberof buttons and non-button objects. Each button is assigned an on-screenposition by the content author and can be navigated and activated by theuser, e.g. via a remote control. Each button is associated a state,which can either be the ‘normal’ (or ‘unselected’) state, the ‘selected’state or the ‘activated’ state. Each button can provide a differentvisual representation in each state in order to give the user feedback.

However, these kinds of menus are rather static as there is no way todynamically add or remove buttons from the screen, without re-renderingthe whole screen. For content authors such more sophisticated menufeatures would be desirable, for example for the design of sub-menus. Insuch a case, additional buttons dynamically appear and disappear on thescreen through user interaction.

The invention provides means to generate such dynamic menus.

SUMMARY OF THE INVENTION

The present invention is based on the assumption that the different menuitems and buttons of an on-screen menu are rendered separately, notpagewise, on top of a static or dynamic background that may remainvisible. “Rendering” means generating values for display pixels.

According to the invention, each button is assigned an additional state,which can either be the ‘enabled’ or the ‘disabled’ state. As a generalrule, this state defines the rendering behaviour of the button. Buttonsthat are in the ‘enabled’ state are typically displayed on the screen,while buttons that are in the ‘disabled’ state are not rendered andtherefore not displayed. Enabled buttons may also be transparent though.

The user can navigate only buttons that are in the ‘enabled’ state, andtheir well known ‘normal’, ‘selected’ or ‘activated’ state is only validwithin the ‘enabled’ state. The user cannot navigate buttons that are inthe ‘disabled’ state. Any attempt to do that is ignored by the decoderaccording to the invention.

Each button within the menu is assigned an on-screen area and a uniqueidentifier. Usually the on-screen area of buttons will be rectangular,or a combination of rectangular partial areas.

According to the current invention, buttons are organized in groups, andall buttons obey to certain rules, which are described in the following.

-   -   The number of buttons belonging to one button group can be one        or more. There are no empty button groups.    -   A button cannot belong to more than one button group.    -   The on-screen area of any button belonging to a first button        group does not overlap with the on-screen area of any other        button that is not belonging to the same button group.    -   Each button within a button group must be in one of the two        states: ‘enabled’ or ‘disabled’.    -   Each button is assigned an initial state, which is either the        ‘enabled’ or the ‘disabled’ state.    -   Not more than one button within a button group can be in the        ‘enabled’ state at a time, i.e. rendered on the screen. Note        that the ‘enabled’ state does not imply user-visibility; e.g. an        enabled button is not visible to the user if it is represented        only through transparent pixels.    -   For each button within a button group neighbourhood information        for button navigation can be defined, saying e.g. which other        button to select when the user presses the LEFT, RIGHT, UP or        DOWN button. This neighbourhood information is only valid when        the button is in the ‘enabled’ state. The user cannot navigate        to disabled buttons.    -   The on-screen areas of a first button of a first button group        and a second button of the same group, i.e. their visible        representations, may overlap. They will not be visible        simultaneously since they belong to the same button group, and        only one of them can be in the ‘enabled’ state at a time.

Further, a new command is defined, based on the invention. This commandcan e.g. be associated with a button, and it is used to dynamicallyswitch between the ‘enabled’ and the ‘disabled’ state of another button.In state-of-the-art menus, activating a button already may encompass theexecution of one or more commands. The proposed command is activated inthe same way and is therefore compatible with the state-of-the-artframework. Other effects of activating a button are commonly that thebutton changes its appearance, colour etc.

One aspect of the invention is the definition of a command for enablingor disabling buttons. The information about which button to enable ordisable is provided through the button identifier as a parameter of thecommand.

For each button there can be defined one or more button commands thatare executed upon activation of the button. The command or set ofcommands associated with a button is also referred to as a buttonhandler. The execution of button commands is only possible when thebutton is in the ‘enabled’ state. There may be ‘empty’ buttons howeverthat have no associated button command. The disabling of a button mayclear the button visibility by substituting it with transparent pixels.

The inventive button command does usually not change the ‘enabled’ or‘disabled’ state of its own button. This means that if an enabled buttonis activated, the corresponding button command that is executed uponactivation may switch the ‘enabled’/′disabled′ state of other buttons,but it may not switch its own button to the ‘disabled’ state, exceptwhen its button handler has already scheduled the selection of anotherbutton. There may however other commands be executed that comprise e.g.disabling the whole menu. Enabling one button of a group implicitlydisables all other buttons within that group.

For each button group a display area is defined where its buttons may berendered. This area is in the following called a button group area. Itis usually rectangular, but can in principle have other shapes. Thevisible button may have any shape as long as it is within its respectivebutton group area. E.g. it is possible to render a circular buttonwithin a rectangular area. The screen pixels that belong to a buttongroup area, but not to an enabled button within said button group area,are rendered transparent.

For button group areas according to the invention it is characteristicthat no possible button position within a button group may overlap withany possible button position of another button group, so that the buttongroup areas of different button groups may not overlap at all.

This means that the screen can be considered as a number ofnon-overlapping button group areas. When the state of any of the buttonsof a button group changes, the decoder according to the invention readsthe position of the respective button group area from a storage medium,usually an internal memory, and then re-renders the area. For each grouponly the enabled button is rendered, wherein the corresponding buttongroup area may comprise any number of transparent pixels.

Advantageously, re-rendering of a button group area never modifiespixels belonging to any other button group area, since different buttongroup areas may not overlap. This allows easier decoders. Further, itallows easier programming of menus, and particularly easier verificationof the respective programming code, e.g. due to static button positionsand static neighborhood relations.

In detail, there are three possibilities for button group areas, asdescribed in the following. They are specialized versions of a generalcase.

The first possibility is the general case as described above, wherein abutton group area may comprise several non-overlapping partial areas,and in each button group area a button belonging to the respectivebutton group may be rendered visible. Therefore a button that belongs toa button group is usually associated with one partial area of its buttongroup area, and then not more than one of the partial areas of a buttongroup may contain an enabled button. In principle it is possible thoughthat an enabled button is present in more than one of the partial areasof its button group, so that a single button may consist of severalequivalent parts. When the state of any of the buttons of a button groupchanges, the decoder according to the invention reads the positions ofthe partial areas of the respective button group from a storage mediumand renders all partial areas new. Particularly, it renders not morethan one visible button, namely the enabled button.

The second possibility is that a button group area is a contiguous area,e.g. a rectangular area. This means that a cohesive area is defined foreach button group, which area comprises all possible positions ofbuttons belonging to that button group. As mentioned before, the areasthat belong to different button groups may not overlap, and the visiblebutton needs not necessarily fill the allowed area, i.e. the buttonneeds not have the size and shape of the button group area, but it mustbe fully within the area corresponding to its group. Therefore, buttonsbelonging to different groups may not overlap. Further, it is easy tofully delete a first button belonging to a first button group whendisplaying a second button belonging to the same button group, becausein this case only the button group area belonging to the respectivebutton group needs to be re-rendered, which is a single contiguous area;it is not necessary to re-render other parts of the screen. Thus, noremains of the previously shown button are visible. All buttons within abutton group use the same on-screen area. This is the preferredpossibility.

The third possibility is that all buttons of a button group haveidentical areas, i.e. button size and position on the screen. This isthe easiest case, with respect to decoder implementation, menuprogramming and verification, because rendering a button that belongs toa certain button group necessarily deletes another button of the samebutton group that was previously visible on the same position. Though itprovides a less flexible menu than the other two possibilities.

In principle a button group can also contain non-button objects, i.e.menu items that are visible but not selectable. A non-button object thatbelongs to a button group has a state assigned, the state being‘enabled’ or ‘disabled’, and can be rendered visible only if it isenabled. Enabling and disabling is done through button handlersassociated with menu buttons.

The invention provides more sophisticated menu features, as e.g.demanded by content authors, which features allow easy decoding. Inparticular, the invention provides means to generate dynamic menus,wherein buttons can be dynamically removed or added to a menu.

With the invention, a content author is able to easily definehierarchical menus and sub-menus being represented by a flat datastructure. Particularly the programming and verification of menus iseasier than with known methods. An advantage of the invention is thatthe graphics decoder needs not consider the whole menu for any menuoperation, but it may simply handle isolated button groups instead. Thedata that describe the initial menu structure are read from a storagemedium, usually a removable storage medium, e.g. optical disc, and arethen stored on a temporary storage medium, e.g. memory, which isconnected to the decoder. When the menu is operated, the variableswithin the temporary storage hold the current state.

When a button is invisible, this can either mean that it is disabled andcan therefore not be selected or activated, or it is enabled and markedinvisible, e.g. has a special flag or only transparent pixels. In thelatter case it can be selected, and usually will be automaticallyactivated upon selection, so that associated commands are executed and avisible button is selected. It is also possible to concatenate invisiblebuttons, as long as the last button command selects a visible button.

Claim 1 discloses a method for generating a menu using such buttongroups. An apparatus that utilizes the inventive method is disclosed inclaim 2. A storage medium holding a respective data structure isdisclosed in claim 3. A method for recording a respective data structureon a storage medium is disclosed in claim 4.

Further objects, features and advantages of the invention will becomeapparent from a consideration of the following description and theappended claims when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are described with reference tothe accompanying drawings, which show in

FIG. 1 a menu screen with disabled submenus;

FIG. 2 a menu screen with enabled first submenu;

FIG. 3 a menu screen with enabled second submenu;

FIG. 4 an authoring option for submenu selection;

FIG. 5 a menu screen with selected submenu item;

FIG. 6 a button group area according to first possibility;

FIG. 7 a button group area according to second possibility;

FIG. 8 a button group area according to third possibility;

FIG. 9 a screen with menu icon;

FIG. 10 a screen with menu icon and enabled menu;

FIG. 11 an initial multi-activation menu screen after first activationof a feature type button;

FIG. 12 a multi-activation menu screen after second activation of afeature type button;

FIG. 13 a multi-activation menu screen after third activation of afeature type button;

FIG. 14 a menu screen with conditionally enabled item;

FIG. 15 initial view of a breadcrumb menu;

FIG. 16 buttons included in initial view of a breadcrumb menu;

FIG. 17 and FIG. 18 transition from first to second view in breadcrumbmenu;

FIG. 19 and FIG. 20 transition from second to third view in breadcrumbmenu; and

FIGS. 21, 22 and 23 appearances of selected and unselected, butpreviously selected, buttons in breadcrumb menu, during transition tosubmenu.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the initial view of a menu page on a display screen S, withonly an “Audio Language” button VB1 and a “Subtitle Language” button VB2enabled and visible. The other buttons BG belong to submenus of eitherof the visible buttons and are invisible, as defined through adata-segment that describes the menu and that is contained in abitstream on the medium. According to the invention, these buttons BGbelong to separate button groups and are initially disabled, and thusinvisible. Moreover, also the two visible buttons VB1, VB2 may belong toseparate button groups. The data segment can be called interactivecomposition segment (ICS). In the initial view shown in FIG. 1 none ofthe visible buttons VB1, VB2 is activated. Usually one of the visiblebuttons is initially selected by default. If in the shown case the userpresses e.g. the RIGHT button on the remote, nothing would changebecause there is no button activated yet. Generally, if neighbourhoodrelations are defined that lead to disabled buttons, the decoder ignoresthe relations as long as the neighbour buttons are disabled. Pressinge.g. the UP or DOWN button would select either of the visible buttonsVB1, VB2. Activating the “Audio Language” button VB1 by selecting thebutton VB1 and pressing on a remote e.g. an “OK” button would lead to amenu display modification, as shown in FIG. 2.

In FIG. 2 the “Audio Language” button VB1 is activated, and the buttoncommands associated with it enable the buttons BGA to the right.Consequently, these buttons BGA are rendered visible, allowing to selectand activate one of them, and thus to select an audio language.

FIG. 3 shows a situation where e.g. starting from FIG. 2 the “AudioLanguage” button VB1 was not activated, but the DOWN button was pressedso that the “Subtitle Language” button VB2 gets selected. Then the“Subtitle Language” button VB2 was activated e.g. by the user pressingan “OK” button on the remote control. The effect is that the fourbuttons BGS to the right are rendered, presenting subtitle options, andin particular these buttons are rendered in the same positions as thefour buttons BGA to the right were rendered for audio options in FIG. 2.This corresponds to the third possibility for positioning buttons ofbutton groups, as described above, since buttons that have the sameposition but belong to different submenus belong to the same buttongroup. The buttons BGS shown in FIG. 3 are different from the buttonsBGA shown in FIG. 2, since they have different functions, namely allowselection of a subtitle language. The buttons BGS represent the“Subtitle” range of buttons for each of the button groups, while thebuttons BGA in FIG. 2 represent the “Audio” range of buttons of the samebutton groups. In this particular example, not only the position butalso the appearance and the languages of the corresponding buttons ofthe shown submenus are the same. E.g. in FIG. 3, only from the selectedbutton VB2 is visible to which submenu the buttons BGS refer. Therefore,when one of the submenu buttons BGS is selected, the correspondingsuperior button VB2 should look different from an unselected button,though it is neither selected nor activated.

FIG. 4 shows a menu where a graphical user hint GH, in the form of asmall arrow, appears in the visible buttons VB1, VB2, showing thatrelated submenus exist. When the “Audio Language” button VB1 isactivated or when it is selected and the RIGHT button is pressed on theremote, then its button handler selects an invisible button INB beingdefined in the neighbourhood information of the “Audio Language” buttonVB1 as neighbour to the right. The invisible button INB is a so-calledauto-action button, since it automatically switches from the selectedstate to the activated state, so that its button handler is executed.The button handler comprises a command to render the four buttons BGA onthe right visible, without any of them being activated, and a command toselect the “English” button. The invisible button INB has the same datastructure as the other buttons. If the RIGHT button is pressed while the“Audio Language” button is selected, the audio options become visible.

In the next step, one of the new buttons on the right can be selected,as shown in FIG. 5. There are four different button groups BGA, namely‘English’, ‘Japanese’, ‘Korean’ and ‘Dutch’. Further, it is possiblethat the “Audio language” and the “Subtitle Language” buttons belong tobutton groups. It is also possible though to combine button groups andsingle buttons. From the data structure point of view, single buttonsmay also form a button group with only one element. In the situationdepicted in FIG. 5, the “Audio Language” button looks selected oractivated, and for each of the submenu button groups BGA the buttonsrepresenting the options for audio are enabled and visible. They arerendered at the same positions where also the buttons for subtitleoptions would be rendered, if the “Subtitle Languages” were selected.Therefore the buttons belonging to the same button group are overwritingeach other. One of the submenu buttons is selected, and therefore the“Audio Language” button must be deselected, as described later for FIG.23. The selected submenu button can be a default button, e.g. ‘English’is a predefined default, or it can be the currently used option, or anyother type of default.

FIG. 6-8 show examples for the three above-mentioned possibilities fordefining button group areas. The area of a button group is generallydefined through the sum of all on-screen areas of the buttons thatbelong to that button group. Further, the position of different buttonsthat belong to the same button group may differ, as long as they arewithin the area specified for their button group. For practical reasons,i.e. due to the column and row structure of a typical display, thebutton group area and partial areas will usually be rectangular, thoughthey can in principle have any shape.

FIG. 6 shows the first possibility for definition of a button group, asdescribed above. A first button group BG61 comprises three buttons B#1,B#4, B#6 with three separate, non-coherent areas. A second button groupBG62 also comprises three buttons B#2, B#3, B#5 with three separate,non-coherent areas. According to the definition of button groups, notmore than one button per button group BG61,BG62 is enabled at a time,and may be visible. Thus, only one of the buttons B#1, B#4 and B#6, andonly one of the buttons B#2, B#3, B#5 may be enabled (and visible) at atime, while the others are rendered transparent. Further, none of theindividual button areas of the first button group BG61 may overlap withany individual button area from the other button group BG62. It ispossible though to surround, even fully surround, a button group area ofa first button group with partial areas belonging to a second buttongroup. In this example, the enabled and visible buttons fully covertheir respective button group areas. In another embodiment though itwould be possible that areas of buttons that belong to the same groupmay overlap, e.g. B#2 and B#5. This is because they may not be visibleat the same time, and when one of them is rendered visible, all partialareas of the button group area are re-rendered and thus cleared, i.e.rendered transparent.

FIG. 7 shows the preferred embodiment, where a single area is definedfor every button group, and all buttons belonging to that button groupare positioned within that area. A button group BG71 has a defined areawhere all its buttons B#11, B#12 are rendered. Another button group BG72has another area for its buttons B#21, B#22. Also here, button groupareas of different button groups may not overlap. The position ofdifferent buttons B#11, B#12 that belong to the same button group BG71may differ, as long as they are within the specified area.

FIG. 8 shows a special case of the preferred embodiment, where allbuttons of each button group have exactly the same position, thusoverwriting each other. Therefore, the area of a button is identicalwith the button group area in this case. A first button group comprisesan enabled, and therefore visible, “Audio Language” button BG81 and oneor more disabled, invisible buttons BG81′. Though the disabled buttonsBG81′ are drawn visible in the figure for clarity, they have exactly thesame display position as the visible button BG81.

FIG. 9 shows an example where a menu is represented only through a menuicon MM, while the rest of the screen shows an audio-visualpresentation, e.g. a movie. A small icon MM is displayed on the screen,indicating that a menu is available. The icon MM does not disturb theviewer who is watching a movie. When the viewer activates the menu, e.g.through pressing either a dedicated button or the “OK” button on theremote control, further buttons of the menu are revealed, as shown inFIG. 10. The user can operate the menu to make selections, e.g. selectan audio language or a subtitle language with respective buttons AL, SL.If e.g. the “Audio Language” button AL is selected and activated, anaudio language submenu is rendered visible, as shown in FIG. 11. It maycomprise e.g. the “Audio Language” button ALE to indicate the currentposition within the hierarchical menu, and initial language optionbuttons L1, . . . , L4 for English, Japanese, Korean and Dutch. The“Audio Language” button AL1 has an indication MI1 for indicating thatfurther options exist. In this example, the further options can beaccessed by repeated activation of the “Audio Language” button AL. Thisis called multi-activation. If this button AL is activated a secondtime, audio language buttons L5, . . . , L8 for Spanish, French, Greekand Polish appear, and after a third activation there are audio languagebuttons L9, . . . , L12 for Danish, Norwegian, Finnish and Swedish.After a fourth activation of the “Audio Language” button AL however theinitial menu is displayed again, as shown in FIG. 10. The menu can beiconified again with the dedicated menu button.

Although the viewer has the impression that only the text within theoption buttons changes, it is technically difficult and error-prone toprogram such a menu with known methods and data structures. Inparticular, for the verification of the programmed menu data it isnecessary to test all possible combinations of buttons, in order to besure that the menu works correctly. An implementation using buttongroups according to the invention is advantageous, because the menuneeds to be verified with only one button from each button group, andthe button group mechanism can be verified separately, only once.Further, it is easy for the menu programmer to rearrange the options,and thus modify the button groups.

In the described example, a first button group comprises the buttons forEnglish L1, Spanish L5 and Danish L9.

A second button group comprises the buttons for Japanese L2, French L6and Norwegian L10.

A third button group comprises the buttons for Korean L3, Greek L7 andFinnish L11. A fourth button group comprises the buttons for Dutch L4,Polish L8 and Swedish L12. Those buttons of the different button groupsthat are enabled and visible at the same time can be regarded as alogical layer, though from the data structure point of view they areindependent from each other. They are only at the same time enabled andvisible.

But also the “Audio Language” button AL is not a single button, sincedepending on the current state of the other menu buttons it hasdifferent functions. Particularly, the functions differ in which optionbuttons must be enabled upon activation of the current “Audio Language”button. E.g. activation of the “Audio Language” button AL1 in FIG. 11causes that the option buttons L5, . . . , L8 shown in FIG. 12 areenabled, while activation of the identical-looking “Audio Language”button AL2 in FIG. 12 causes that the option buttons L9, . . . , L12shown in FIG. 13 are enabled. Therefore, a fifth button group maycomprise the different “Audio Language” buttons AL1, AL2, AL3 thatbelong to the logical layers. Alternatively, it is possible that the“Audio Language” buttons AL1, AL2, AL3 are identical, and the buttoncommand takes into account which button from the button groups arecurrently enabled, and the command enables the next element from eachbutton group.

FIG. 14 shows an example for conditional enabling. Buttons can beenabled or disabled depending on user settings or player settings. E.g.there can be three versions of a movie on a disc: a ‘children's cut’, a‘theatrical cut’ and a ‘directors cut’. When the disc is inserted intothe player, the initial menu may show a non-selectable button NSB withe.g. the title of the movie, and three selectable buttons SB1, SB2, SB3for the reproduction options. A user can however set a parental level,and thus allows the ‘children's cut’ and the ‘theatrical cut’, butrejects the ‘directors cut’. The screen may then show only twoselectable buttons SB1, SB2 for the two allowed options. For theforbidden option however there is no visible button available, since itis rendered transparent.

According to the invention, this menu behaviour can be technicallyachieved by using enable/disable commands and button groups. One or moreof the option buttons SB1, SB2, SB3 may belong to separate buttongroups, and according to specified settings for each button group adefined member is enabled and rendered visibly. In the current example,the “Director's cut” button belongs to a button group SB3 according tothe invention, with an associated button group area, and the parentallevel setting of the player causes the initial button handler to disablethe respective button, i.e. to render the button group area transparent.Also other setting types can be utilized, e.g. reproduction optionsdepending on player type, audio equipment type etc.

As a further embodiment of the invention, so-called breadcrumb menus caneasily be constructed. Breadcrumb menus are generally menus where thepreviously pressed button that belongs to another hierarchy remainsvisible, so that the user can see which button was selected, and to whatthe currently displayed option buttons refer. This is particularlyuseful for hierarchical menus. In the data structure utilized by theinvention, hierarchy is given implicitly by neighbourhood relations.

FIG. 15 shows a menu screen with three buttons AMB, ALMB, SLMB thatbelong to the same hierarchical level. One of the menu buttons AMB isfor multi-angle selection. It is selected, and three angle select optionbuttons ASB are displayed on the right. Each of these visible optionbuttons ASB belongs to a separate button group and was rendered visiblebecause the “Angle” menu button AMB is selected. The other members ofthese button groups are disabled and thus invisible.

FIG. 16 shows that the menu comprises also other, invisible buttons IB1,. . . , IB4. These are used to define what should happen at transitionsbetween the higher level menu buttons AMB, ALMB, SLMB.

When the “Angle” menu button AMB is selected, like in FIG. 15, and theuser wants to select the “Audio Language” menu button ALMB, he pressesthe DOWN button on his remote, because the “Audio Language” menu buttonALMB is displayed below the “Angle” menu button AMB. A dynamic menu, assupported by the invention, may perform the following:

First, the button that is defined as DOWN neighbour of the “Angle”button is selected, which is in this example an invisible button IB1.This is the state shown in FIG. 17. Although invisible buttons are notrepresented on the display, they may have a display area or positionassigned due to data consistency, e.g. if the same data structure isused for visible and invisible buttons. For illustrative purpose howeverthe figures show also invisible buttons, at their logical positions.

Then, after the invisible button IB1 was selected, it is automaticallyactivated (auto_action_flag==true in Tab.1), and its button handlerexecutes the following commands: first it disables the menu optionbuttons ASB relating to the “Angle” menu button AMB, thus making theminvisible, second it enables the option buttons ALSB that belong to themenu button the user wants to select, which is the “Audio Language” menubutton ALMB, and finally it selects the “Audio Language” menu buttonALMB, thereby deselecting itself. This is shown in FIG. 18. FIG. 19 andFIG. 20 show the corresponding transition from the “Audio Language” menubutton ALMB to the “Subtitle Language” menu button SLMB using anotherinvisible button IB3, wherein the audio language submenu buttons ALSBare replaced by subtitle language submenu buttons SLSB. Further, thereare invisible buttons IB2, IB4 for the opposite transitions.

As a result, the menu option buttons ASB, ALSB, SLSB always match theselected menu button AMB, ALMB, SLMB without the selected menu buttonbeing activated. The user may not perceive the intermediate states, theinvisible buttons or the short time the described transitions take,usually in the range of milliseconds. According to the invention, themenu option buttons ASB, ALSB, SLSB are implemented as members of buttongroups. Buttons on the same position that belong to different submenusform a button group. This allows an easy menu data structure andtherefore simplified programming and verification. In particular, buttongroups may implicitly handle the disabling of obsolete submenu optionbuttons and the enabling of the correct submenu option buttons thatbelong to the newly selected menu button. Since not more than one buttonfrom a button group may be enabled, and therefore visible, it issufficient to select for each button group the new button to be enabled.This implicitly disables the previously enabled button of the group, andthe pixels that belong to the button group area are overwrittenaccording to the bitmap representation of the new button. The rest ofthe display may remain unchanged. Therefore there is no need for thedecoder to analyse which buttons were visible before, which button mustbe replaced, which area it occupied and if any button areas overlap.

Another embodiment of the invention, being an exemplary implementationof the above-described breadcrumb effect, is shown in FIG. 21-23. When ahierarchical menu button is selected, e.g. the “Angle” menu button AMB1in FIG. 21, it changes from the normal state to the selected state, andits representation looks different, e.g. highlighted. This is caused bydifferent bitmap representations corresponding to the states of abutton. When the “Angle” menu button AMB1 is activated, it remains onlya very short time in the activated state. Its appearance during thistime may differ from the selected state, but the user will hardly seeit. When the button is activated, its button handler may select aninvisible button INB that is used to render the submenu buttons ASBvisible, as described above. This situation is shown in FIG. 22. At thistime, when the invisible button INB is in the selected state, the“Angle” menu button is not selected, since only one button of the menucan be selected at a time—otherwise the decoder could not detect towhich button a user command refers. The “Angle” menu button is in thenormal state instead. But in order to achieve the breadcrumb effect,i.e. indicate the menu button to which the current submenu buttons ASBrefer, it would be desirable to give the menu button AMB1 anotherappearance. This can be achieved with the button groups according to theinvention, e.g. by generating an “Angle” button group.

The default “Angle” button AMB1, like any menu button, has the threestates normal, selected and activated. Another button, e.g. an“Angle_Select” button AMB2 belonging to the same button group lookssimilar to the default “Angle” button AMB1 and has the same displayposition, but differs slightly. E.g. its normal state bitmap may be thesame as the default buttons selected or activated state bitmap. Asdescribed before, the invisible button INB is automatically activatedupon selection. It may e.g. render the submenu buttons ASB visible, thenenable the “Angle_Select” button AMB2 (in the normal state), thusimplicitly disabling the previously visible “Angle” button AMB1, andfinally select one of the submenu buttons ASB 1, thus deselectingitself. This is shown in FIG. 23. The effect is that the user mayrecognize the button AMB2 as the same button AMB1 like before, and thatthe button AMB2 looks selected or activated, but actually it isdeselected. This allows giving a button virtually more differentrepresentations than states, e.g. colours, shapes, text etc., byreplacing it with other buttons. The inventive button groups allow aneasy handling of these buttons, and provide a simple mechanism todetermine the correct values for pixels within the button group area.

The group structure provides information for the menu decoder, theinformation defining which on-screen area needs update. Because within abutton group not more than one button is active at a time, theactivation of another button within a group implies the deactivation ofthe first button of the same group. This is an advantage for authoring,since it makes it easier to author menus.

Especially in the case of prerecorded media, e.g. prerecorded Blu-raydiscs, a verification process is performed on any title before it isreleased to check if the data-structure meets the specification. Theinvention allows for easy verification while providing enhanced featuresto the content author when creating dynamic menus.

In the following, the syntax of a data segment shown in Tab.1 isdescribed, which may be contained in a bitstream and describes theinitial menu screen, being an exemplary implementation. It describes thecase that the button group area is defined according to the secondpossibility described above.

TABLE 1 Exemplary Syntax of data segment describing a menu No. of Syntaxbits Mnemonics 1 interactive_composition_segment( ) { 2 segment_type 8bslbf 3 segment_length 16 uimsbf 4 composition_number 16 uimsbf 5composition_state 2 bslbf 6 reserved 6 bslbf 7 command_update_flag 1bslbf 8 reserved 7 bslbf 9 composition_time_out_pts 33 uimsbf 10reserved 7 bslbf 11 selection_time_out_pts 33 uimsbf 12 reserved 7 bslbf13 UO_mask_table( ) 64 bslbf 14 animation_frame_rate_code 8 uimsbf 15default_selected_button_number 8 uimsbf 16default_activated_button_number 8 uimsbf 17 while (processed_length <segment_length) { 18  button_group( ) { 19  button_group_horizontal_position 16 uimsbf 20  button_group_vertical_position 16 uimsbf 21  button_group_horizontal_size 16 uimsbf 22   button_group_vertical_size16 uimsbf 23   default_enabled_button_number 8 uimsbf 24   num_buttons 8uimsbf 25   for (i=0; i<num_buttons;i++) { 26    button_number 8 uimsbf27    numerically_selectable_flag 1 bslbf 28    reserved 7 bslbf 29   auto_action_flag 1 bslbf 30    reserved 7 bslbf 31   button_horizontal_position 16 uimsbf 32    button_vertical_position16 uimsbf 33    neighbor_info( ) { 34     upper_button_number 8 uimsbf35     lower_button_number 8 uimsbf 36     left_button_number 8 uimsbf37     right_button_number 8 uimsbf 38    } 39    normal_state_info( ) {40     start_object_id_normal 16 bslbf 41     end_object_id_normal 16bslbf 42     repeat_normal_flag 1 bslbf 43     reserved 7 bslbf 44    }45    selected_state_info( ) { 46     start_object_id_selected 16 bslbf47     end_object_id_selected 16 bslbf 48     repeat_selected_flag 1bslbf 49     reserved 7 bslbf 50    } 51    actioned_state_info( ) { 52    start_object_id_activated 16 bslbf 53     end_object_id_activated 16bslbf 54    } 55    num_of_button_commands 8 uimsbf 56    for( cmd_id =0;     cmd_id <     num_of_button_commands;     cmd_id++ ) { 57    button_command[cmd_id] 96 bslbf 58     } 59    } 60   } 61  } 62 }

The notation used in Tab.1 uses while-loops and for-loops. Loops howeverare only a means to generalize the notation, since the actual bitstreamwill include data for the single passes or instances of the loop.

Between 1.17 and 1.61 is a loop over the complete data segment of lengthsegment_length. A data segment may include any number of button groups.

In 1.18 is defined that the following lines, until 1.60, refer to thedefinition of a button group. The identifier of the group is the valuegiven in round brackets. In 1.19-22 the respective position on thescreen is defined for the current button group, also referred to asbutton group area in this application. It is defined by its horizontaland vertical size and the position of its reference point. In this casethe button group area is only one rectangular, but as described beforeit may be other areas or a plurality of rectangulars. In that case1.19-22 would be repeated once for each partial area.

The parameter in 1.23 defines which of the buttons of the current groupis enabled by default. The decoder uses this value to initially load aregister that relates to the current group and holds a variable. Thisvariable specifies the number of the currently enabled button, and canbe modified during operation of the menu. It may also be assigned avalue that corresponds to none of the buttons, so that all buttons ofthe group are disabled. This mechanism ensures that not more than onebutton within a group is enabled. Two other parameters that are used toinitialize variables that may be modified during menu operation aredefault_selected_button_number (1.15) anddefault_activated_button_number (1.16).

In 1.24 the number of buttons in the current group is defined. The loopbeginning in 1.25 covers all buttons of the group and defines for eachbutton a reference number (1.26), if it is numerically selectable(1.27), if it automatically executes its commands when it is selected(1.29), its position within the button group area (1.31-32), itsneighbour buttons (1.33-38), and address ranges indicating where thebitmap representations corresponding to the different buttons states canbe read. For every button, one or more commands can be defined. Thenumber of commands of the current button is specified in 1.55 by theparameter num_of_button_commands. The actual commands of the buttonhandler are defined in 1.56-58.

The invention is usable for all kinds of presentation devices that haveaccess to a display and contain a decoder for processing menu datastructures read from e.g. DVDs, Blu-ray discs or other media. Further,the invention is usable for generating such data structures.

According to the invention, a decoder for decoding a data stream, thedata stream comprising menu data for a visually displayable menu, andthe menu comprising separately rendered menu items including selectablemenu buttons, includes (i) means for defining at least one group of menuitems, the group comprising one or more menu items, wherein a menu itemmay not belong to more than one group, (ii) means for associating tosaid group a defined area on the display, and (iii) means for assigninga state to each of said menu items belonging to a group, the state being“enabled” or “disabled”, wherein only an enabled menu item may bedisplayed, and wherein not more than one menu item within a group may beenabled simultaneously.

Further, a displayed menu item that belongs to a group is displayedwithin the area associated with said group, wherein the areas ofdifferent groups may not overlap and no display pixel may belong to morethan one group.

Further, a menu item may have an associated command, which is executedupon activation of the menu item and comprises enabling or disabling ofanother menu item.

The invention claimed is:
 1. A method for generating a displayable menupage from data of a menu data segment, the menu page comprisingseparately rendered selectable menu buttons, comprising: accessingdefinition of at least one group of two or more menu buttons from themenu data segment, wherein the definition of the at least one group inthe menu data segment comprises a parameter indicating the number ofmenu buttons in a respective group of the at least one group, andwherein each of the two or more menu buttons has associated a definedarea on a display and each menu button that belongs to the displayablemenu page is separately rendered, and for each of the two or more menubuttons a number of commands is defined, and wherein a menu buttonbelongs to not more than one group of the at least one group; andassigning a state to each separately rendered menu button, the statebeing “enabled” or “disabled”, wherein only an enabled menu button isdisplayed, wherein a menu button in the “enabled” state may have afurther state of “normal”, “selected” or “activated”, and wherein themenu button is considered to be a same menu button irrespective of itsstate being the “disabled” state, the “enabled” and “normal” state, the“enabled” and “selected” state or the “enabled” and “activated” state,and wherein not more than one menu button within a group may be enabledsimultaneously.
 2. Apparatus for processing a data stream, the datastream comprising menu data for a displayable menu page, wherein thedisplayable menu page comprises selectable menu buttons to be separatelyrendered, the apparatus including means for separately rendering eachmenu button that belongs to the displayable menu page; means fordefining, based on data from said data stream, at least one group of twoor more menu buttons, wherein a menu button belongs to not more than onegroup, and for each of the two or more menu buttons a number of commandsis defined, and wherein based on the data from said data stream, aparameter indicating the number of menu buttons in a respective group isdefined for the at least one group; means for associating with each ofsaid menu buttons a defined area on a display; means for assigning astate to each of said separately rendered menu buttons belonging to agroup, the state being “enabled” or “disabled”, wherein only an enabledmenu button is displayed, wherein a menu button in the “enabled” statemay have a further state of “normal”, “selected” or “activated”, andwherein the menu button is considered to be a same menu buttonirrespective of its state being the “disabled” state, the “enabled” and“normal” state, the “enabled” and “selected” state or the “enabled” and“activated” state, and wherein not more than one menu button within agroup may be enabled simultaneously.
 3. A removable data storage mediumcontaining audio-visual data and a menu data segment for generating adisplayable menu page relating to the audio-visual data, the menu pagecomprising separately rendered selectable menu buttons, wherein for themenu data segment at least one group of two or more menu buttons isdefined in said menu data segment, wherein a definition of the at leastone group in the menu data segment comprises a parameter indicating thenumber of menu buttons in a respective group of the at least one group,and wherein each of the two or more menu buttons has associated adefined area on a display, and for each of the two or more menu buttonsa number of commands is defined and each menu button that belongs to thedisplayable menu page is separately rendered; a menu button belongs tonot more than one group of the at least one group; a state is assignedto each separately rendered menu button, the state being “enabled” or“disabled”, wherein only an enabled menu button is displayed, wherein amenu button in the “enabled” state may have a further state of “normal”,“selected” or “activated”, and wherein the menu button is considered tobe a same menu button irrespective of its state being the “disabled”state, the “enabled” and “normal” state, the “enabled” and “selected”state or the “enabled” and “activated” state, and wherein not more thanone menu button within a group may be enabled simultaneously.
 4. Amethod for recording audio-visual data and a menu data segment forgenerating a displayable menu page relating to the audio-visual data ona removable data storage medium, the menu page comprising separatelyrendered selectable menu buttons, the method comprising: creating, insaid menu data segment, data for at least one group of two or more menubuttons, wherein a definition of the at least one group in the menu datasegment comprises a parameter indicating the number of menu buttons in arespective group of the at least one group, and wherein each of saidmenu buttons has associated a defined area on the display, and for eachof the two or more menu buttons the number of commands is defined andeach menu button that belongs to the displayable menu page is separatelyrendered, wherein a menu button belongs to not more than one group ofthe at least one group, and wherein upon generating a menu from saidmenu data segment, a state is assigned to each menu button of said atleast one group of menu buttons, the state being “enabled” or“disabled”, and wherein only an enabled menu button may be displayed andmay have one of the states “normal”, “selected” or “activated”, andwherein the menu button is considered to be a same menu buttonirrespective of its state being the “disabled” state, the “enabled” and“normal” state, the “enabled” and “selected” state or the “enabled” and“activated” state, and wherein not more than one menu button within agroup may be enabled simultaneously; and recording said menu datasegment and the audio-visual data on said removable data storage medium.